sdl2-compat: Added initial .gitignore

From 0667c71c7ca26c7c406ce2e0aa29775799e13758 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Tue, 29 Nov 2022 09:43:10 -0500
Subject: [PATCH] Added initial .gitignore

This is just my personal build directory. Other things will probably
trickle in here later.
---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4b08176
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+cmake-build